RE: Microsoft Writing Secure Code

If you want a book on writing secure code then, "designing secure web
apps" is *Not* the book you need (hence the title!) you need "Writing
Secure Code 2nd Ed", (hence the title :)

[Writing Secure Code] http://www.microsoft.com/mspress/books/5957.asp
[Protect Your PC] http://www.microsoft.com/protect
[Blog] http://blogs.msdn.com/michael_howard

[On-line Security Training]
http://mste/training/offerings.asp?TrainingID=53074


-----Original Message-----
From: Damhuis Anton [mailto:[email protected]] 
Sent: Tuesday, January 04, 2005 1:53 AM
To: [email protected]
Cc: Michael Howard
Subject: RE: Microsoft Writing Secure Code


I have read the book "Designing Secure Web-based Applications", found it
quite informative but also somewhat disappointing.

I was (at the time) looking for a book that assists with "writing secure
code". Thus how code should be written, not the way code interfaces with
security components.

Example:
What is the best way to display User Details:

~~Suedo code Begin ~~
Option 1:
If var_userLevel = USER then
   ... display User info
else
  ... Display Admin Info
end if



Option 2:
If var_userLevel = ADMIN then
   ... display Admin info
else
  ... Display User Info Info
end if



Option 3:
If var_userLevel = ADMIN then
   ... display Admin info
elseif var_userLevel = USER
  ... Display User Info Info
else
  ... Capture Error
end if

~~Suedo code End~~



To me it is Option 3. Somewhat more work, but a lot more secure, then
Option 1. If for some reason someone else writes the code to get the
variable for var_userLevel , and that code is hackable, Option 3 will
withstand the attack a lot better then Option 1. Option 2 in this case
would also be better then Option 1, as Option 1 would display the Admin
info for anybody other then user. Option 2 in this case would revert
back to the lower level of access. Thus just structuring the If stament
differently in Option 1 and 2, already makes the code more secure.

Also by logging all the errors in option 3's last "Else" statement one
can look for any thing overlooked initially (and capture any unknown
hacker attacks -although this is reactively)

Regards
  Anton


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